iwlwifi: dvm: take mutex when sending SYNC BT config command

There is a flow in which we send the host command in SYNC
mode, but we don't take priv->mutex.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1046495

Cc: <stable@vger.kernel.org>
Reviewed-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/dvm/main.c

@@ -252,13 +252,17 @@ static void iwl_bg_bt_runtime_config(struct work_struct *work)
 	struct iwl_priv *priv =
 		container_of(work, struct iwl_priv, bt_runtime_config);
 
+	mutex_lock(&priv->mutex);
 	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
-		return;
+		goto out;
 
 	/* dont send host command if rf-kill is on */
 	if (!iwl_is_ready_rf(priv))
-		return;
+		goto out;
+
 	iwlagn_send_advance_bt_config(priv);
+out:
+	mutex_unlock(&priv->mutex);
 }
 
 static void iwl_bg_bt_full_concurrency(struct work_struct *work)